MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
Lars Peter Riishojgaard
Yan-Qiu Zhu
Global Modeling and Assimilation Office
NASA Goddard Space Flight Center
Preparation for operational assimilation MODIS winds in the DAO
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
Overview
Data assimilation at Goddard and the JCSDA
Characteristics of the MODIS winds
Results from pre-operational testing
Summary and outlook
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
GMAO
New Office at Goddard, formed via a merger of the DAO and NSIPP (NASA Seasonal to Interannual Prediction Project)
Head of Office: Michele Rienecker Modeling
New model targeted for 04; based on fv dynamical core, but with NWP-tuned physics
Analysis Last PSAS-based system being frozen Next system will be based on GSI developed at EMC
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS winds pilot period assimilation experiments in the DAO
Control (all standard observations; no MODIS winds)
MODIS winds used “as is”; no filtering, no modification
Interactive height assignment with pmax=150 hPa
Interactive height assignment with pmax=75 hPa
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
Preparation for operational assimilation of MODIS winds
Extensive experimentation with near-real time winds provided by CIMSS starting 07/02/2002 with versions 1.3r6 and 1.4r1 of the fv-DAS
Main changes with respect to 1.2r5 (pilot period) Increased weight given to ITOVS Additional ITOVS data in polar areas Modified background error covariance
Main metrics Consistency of data delivery Quality of MODIS winds Contribution to forecast skill
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS experiments
I. Basic - MODIS winds used "as is"
II. Height adjustment - the heights of MODIS winds are adjusted by minimizing a cost function
III. Quality indicator-based selection; only MODIS winds with qi larger than 0.80 are used
IV. Retuned o; error for MODIS wind is tuned using maximum likelihood technique
V. “ECMWF filtering”: over land winds used above 400 hPa; over sea, IR winds above 700 hPa and WV winds above 550 hPa
VI. DAOTOVS exclusion: Interactive TOVS retrievals beyond 65S removed
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
Experimental results
Innovations (observation minus forecast residuals) RAOB heights and winds ITOVS heights MODIS winds
Impact Troposphere Stratosphere
Forecast skill
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS IR U, V innovations for NH control (solid), MODIS; Arctic
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS WV U, V innovations for NH control (solid), MODIS; Arctic
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
RAOB U, V innovations for control (solid), MODIS; Arctic
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
RAOB U, V innovations for control (solid), MODIS; SP
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
RAOB height innovations for control (solid), MODIS; Arctic region
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
RAOB height innovations for control (solid), MODIS; South Pole
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
ITOVS height innovations; Arctic region
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
ITOVS height innovations; Antarctic region
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
Mean analyzed 500 hPa geopotential heights for July, 2002, for MODIS I run; NH (top left) and SH (bottom left);
RHS shows difference fields (MODIS minus control).
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
NCEP mean anlyzed 500 hPa heights, July 2002, Anarctica
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
Control minus NCEP MODIS minus NCEP
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
Summary:
MODIS winds complement other observations at the highest latitudes; more so in the SH than in the NH due to the current data sparsity
Consistency of data delivery is acceptable Based on independent verification and
innovation statistics, the quality of the information is acceptable
Positive contribution to forecast skill, but not where one would expect it the most
Current version of fv-DAS is hostile to high-latitude wind information
MODIS Winds Applications to NWP/Data Assimilation studies; Fairbanks, 10/08/2003
Outlook
MODIS winds experiments with new GMAO assimilation system based on GSI (next-generation EMC analysis ) Impact Background error covariance Timeliness
MODIS winds from Aqua ECMWF verification if possible
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